Fix Git Extensions #8211: Incorrect EOL in diff

	- allow the text editor to differentiate between various types of end-of-lines when displaying the EOL marker

Author: lhiginbotham

Project/Src/Document/LineManager/EolMarker.cs

@@ -0,0 +1,10 @@
+namespace ICSharpCode.TextEditor.Document
+{
+    public enum EolMarker
+    {
+        None,
+        Cr, // "\r"
+        CrLf, // "\r\n"
+        Lf // "\n"
+    }
+}

Project/Src/Document/LineManager/LineManager.cs

@@ -168,6 +168,7 @@ private void InsertInternal(int offset, string text)
                 lineCollection.SetSegmentLength(segment, lineBreakOffset - segmentOffset);
                 var newSegment = lineCollection.InsertSegmentAfter(segment, lengthAfterInsertionPos);
                 segment.DelimiterLength = ds.Length;
+                segment.EolMarker = ds.EolMarker;
 
                 segment = newSegment;
                 lastDelimiterEnd = ds.Offset + ds.Length;
@@ -309,25 +310,35 @@ public int GetNextVisibleLineBelow(int lineNumber, int lineCount)
         private DelimiterSegment NextDelimiter(string text, int offset)
         {
             for (var i = offset; i < text.Length; i++)
+            {
+                bool newLineSet = false;
                 switch (text[i])
                 {
                     case '\r':
-                        if (i + 1 < text.Length)
-                            if (text[i + 1] == '\n')
-                            {
-                                delimiterSegment.Offset = i;
-                                delimiterSegment.Length = 2;
-                                return delimiterSegment;
-                            }
+                        if (i + 1 < text.Length && text[i + 1] == '\n')
+                        {
+                            delimiterSegment.Offset = i;
+                            delimiterSegment.Length = 2;
+                            delimiterSegment.EolMarker = EolMarker.CrLf;
+                            return delimiterSegment;
+                        }
+
 #if DATACONSISTENCYTEST
                         Debug.Assert(condition: false, "Found lone \\r, data consistency problems?");
 #endif
+                        newLineSet = true;
+                        delimiterSegment.EolMarker = EolMarker.Cr;
                         goto case '\n';
                     case '\n':
                         delimiterSegment.Offset = i;
                         delimiterSegment.Length = 1;
+                        if (!newLineSet)
+                        {
+                            delimiterSegment.EolMarker = EolMarker.Lf;
+                        }
                         return delimiterSegment;
                 }
+            }
             return null;
         }
 
@@ -352,8 +363,9 @@ private void OnLineDeleted(LineEventArgs e)
 
         private sealed class DelimiterSegment
         {
+            internal EolMarker EolMarker = EolMarker.None;
             internal int Length;
             internal int Offset;
         }
     }
-}
+}

Project/Src/Document/LineManager/LineSegment.cs

@@ -17,6 +17,8 @@ public sealed class LineSegment : ISegment
     {
         internal LineSegmentTree.Enumerator treeEntry;
 
+        public EolMarker EolMarker { get; set; }
+
         public bool IsDeleted => !treeEntry.IsValid;
 
         public int LineNumber => treeEntry.CurrentIndex;

Project/Src/Gui/TextView.cs

@@ -200,7 +200,7 @@ private void PaintDocumentLine(Graphics g, int lineNumber, Rectangle lineRectang
                 if (TextEditorProperties.ShowEOLMarker)
                 {
                     var eolMarkerColor = textArea.Document.HighlightingStrategy.GetColorFor("EOLMarkers");
-                    physicalXPos += DrawEOLMarker(g, eolMarkerColor.Color, selectionBeyondEOL ? bgColorBrush : backgroundBrush, physicalXPos, lineRectangle.Y);
+                    physicalXPos += DrawEOLMarker(g, eolMarkerColor.Color, selectionBeyondEOL ? bgColorBrush : backgroundBrush, physicalXPos, lineRectangle.Y, currentLine.EolMarker);
                 }
                 else
                 {
@@ -1062,17 +1062,41 @@ private void DrawTabMarker(Graphics g, Color color, int x, int y)
             DrawString(g, "\u00BB", tabMarkerColor.GetFont(TextEditorProperties.FontContainer), color, x, y);
         }
 
-        private int DrawEOLMarker(Graphics g, Color color, Brush backBrush, int x, int y)
+        private int DrawEOLMarker(Graphics g, Color color, Brush backBrush, int x, int y, EolMarker eolMarker)
         {
             var eolMarkerColor = textArea.Document.HighlightingStrategy.GetColorFor("EOLMarkers");
 
-            var width = GetWidth(ch: '\u00B6', eolMarkerColor.GetFont(TextEditorProperties.FontContainer));
+            int eolMarkerWidth = 0;
+            string representation = "";
+
+            int backslashWidth = GetWidth(ch: '\\', eolMarkerColor.GetFont(TextEditorProperties.FontContainer));
+            int nWidth = GetWidth(ch: 'n', eolMarkerColor.GetFont(TextEditorProperties.FontContainer));
+            int rWidth = GetWidth(ch: 'r', eolMarkerColor.GetFont(TextEditorProperties.FontContainer));
+            switch (eolMarker)
+            {
+                case EolMarker.Cr:
+                    eolMarkerWidth = backslashWidth + rWidth;
+                    representation = "\\r";
+                    break;
+                case EolMarker.CrLf:
+                    eolMarkerWidth = backslashWidth + rWidth + backslashWidth + nWidth;
+                    representation = "\\r\\n";
+                    break;
+                case EolMarker.Lf:
+                    eolMarkerWidth = backslashWidth + nWidth;
+                    representation = "\\n";
+                    break;
+                case EolMarker.None:
+                default:
+                    return 0;
+            }
+
             g.FillRectangle(
                 backBrush,
-                new RectangleF(x, y, width, FontHeight));
+                new RectangleF(x, y, eolMarkerWidth, FontHeight));
 
-            DrawString(g, "\u00B6", eolMarkerColor.GetFont(TextEditorProperties.FontContainer), color, x, y);
-            return width;
+            DrawString(g, representation, eolMarkerColor.GetFont(TextEditorProperties.FontContainer), color, x, y);
+            return eolMarkerWidth;
         }
 
         private void DrawVerticalRuler(Graphics g, Rectangle lineRectangle)